The study looked at how the water level in a tidal river is connected to floods upstream and tides at the estuary. By analyzing data from different observation stations, they found that the influence of estuary tides on water levels in the river is greater than that of upstream floods. They also discovered that the risk of water levels combining with floods upstream is not always lower than when combining with estuary tides, especially for larger events. This information can help in designing better flood defenses for areas prone to waterlogging along tidal rivers.